A steering control device configured to change a steering characteristic depending on a width of a travel path is known as a steering control device for a vehicle such as a motor vehicle. For example, Patent Literature 1 filed by the applicant of this application discloses a steering control device configured to increase a steering gear ratio and increase a derivative gain of a steering transmission ratio when the travel path width is small compared with when the travel path width is large.
The steering control device disclosed in Patent Literature 1 can increase a traveling performance when the vehicle travels straight on a narrow path compared with a case where the steering gear ratio is not increased even when the travel path width is small. Moreover, the steering control device can increase a traveling performance when the vehicle travels on a narrow and greatly meandering path compared with a case where the derivative gain of the steering transmission ratio is not increased even when the travel path width is small.